Electron discharge device



Feb. 1954 H. c. JONAS ETAL 2,668,927

ELECTRON DISCHARGE DEVICE Filed Nov. 20. 1951 2 Sheets-Sheet l 'NVENTORS RW. SEARS A TTORNEV 38 H. C. JONAS ELECTRON I BEAM Feb. 9, 1954 H. c. JONAS ETAL 2,668,927

7 ELECTRON DISCHARGE DEVICE iled Nov. 20, 1951 2 Sheets-Sheet 2 H. C. JONAS [NI/ENTORS R m SEARS A T ron/vEr Patented Feb. 9, 1954 UNITED STATES; Q FFICE E'IIECTRON DISCHARGE i DEVICE.

Herbert 0. Jonas, Summit; and Raymond" W. Sears, West Orange, N. J., assignors to Bell Telephone Laboratories, Incorporated;- New York, N. Y., a corporation'o'f New York 18- Claims.

Thisinventionrelates to electron discharge devices and more particularly to' such devices of v the electron beam type;

In the copending R W. Sears application discharge device of the typeknown as a flash coder; employable for coding operations in pulse. code modulation systems.

single wide electron beam is'flashed ontos'a. num ber of targets or output electrodesinstantaneous- 1y. rather than' in succession, as occurs when a point. electron beam is swept across the targets. When a point electron beamis employed, either a: single target or a plurality of targets may be.

utilized, because of. the time involved in the sweeping operation. Howevenwhen a flat wide. electron beam is employed, a single target behind. the aperturedscoding plate is insufficient.

Therefore a number: ofseparate targetsor output electrodes are positioned closely adjacent each other directly behind the aperturedicoding plate. Difliculty has been encountered, however,

because'of the large capacitances between these" targets and the electronic and-capacitive coupling between them. Additionally, a low output capacitance and the positioning of-th'e targets so as to preventv secondary electrons from any target reaching adjacent targets are desirable.

his one objector this invention to reduce electronicland capacitive. coupling between the target-elements in an electron discharge device.

It isanother object of this. invention to provide targetor output electrodes for such a device having a low output capacitance.

A' further object of this inven'tion'is'to provide forthe'accurate positioning of a plurality ofoutput "elements closely adjacent each other so a's'not to'be effected by'defocussing'of the'electron beam-or by secondary electron flow between targets;

Astill further object or this 1 invention "is-to provide .an improvedxtarget assembly of output' ele-- ments' for an electron beam discharge devices A: still further obj ect of this invention is-to provide an improved electron beam dischargedeviceof the flash :coder type.-

Theseeand other objectslof this invention are achieved in'one specific embodiment-ofthis=in-.

vention wherein the target assembly. comprises a .plurali-tyof long narrow outputistrips supported on insulatorssuch as mica strips, and mounted within a shield member in a substantially V shaped array; Between each'pairof targetsan Li-section" shield is positioned; the L-section' shields" being supported by the outer shield In a flash coder, a

member. Theinsulating strips on which the collector plates are positioned are-similarly supported by the outer shield member which" has apertures therein allowing passagetherethrough SeriaLNo. 257,365 filed NovemberxZO, 195 1,.there is disclosed a specific embodiment of an electronv of terminals from the output'strips to leads secured to individual button terminals inthe' envelope of the devi'cer The electron beam is focussed onthe: ape'rtured coding: plate: posi tioned immediately before the' target assembly,

' but the positioning o'fltargets or output elements at the apex of the V some distance behind-the apertured' plate does: not interfere with proper coding becausethe focussed'beam only spreads,

on def-ocussing, along the length of the outputelements.

The'output strips are advantageously secured on the insulating stripsirr accordance withthis invention by the terminalsextending from the output strips'to theleads which are attached to the output strips in position. The output strips are further advantageously secured in position on the insulating strips by fingers advantageously integralwith the output stripsand extending through apertures intheinsulating. strips and bent .thereagainst.

It is therefore one feature of this invention; that a target assembly: for an electron :beam dis charge device have a shield positioned. between each target element-and the elements adjacent thereto. Morespecifically, it is a feature of this invention that these shields be of L section and be positioned by ashield member enclosing the tar get assembly.

It is a further feature of this invention that the target or output elements be positioned'in staggered planes andmore specifically in'a V-sh'ap'edarray with the apexof thea'rray farthest from the apertured coding plate 'of the electron dis charge device. I i

It "is I. a Still flirl'lhl' feature of this" invention shapedar'r'aydn the target assembly comprise long narrow "conducting" strips positioned on in sulating strips andsp'eciflcally thiatthese insulat-' ing strips be also positioned by-the shield member enclosing the target assemblyl It is a further featureof this invention that' the' terminals" extending from the output or target strips and attached-to thelea'ds extending to *ter mina'lsuntheenvelope ofthed'evice be bent be hind'theinsulatingstr'ips soasto cl'amp the-out"- put strip onto the insulating strip. Further it is a feature of this invention that fingers extend from the output strips through apertures in the insulating strips and are bent behind the insulating strips to further clamp the output strips to the insulating strips. More specifically, in accordance with these features of this invention, the terminals and fingers extending from the output strips may be formed integral therewith.

A complete understanding of this invention and of the various features thereof may be gained from consideration of the following detailed description and the accompanying drawing, in which:

Fig. 1 is a side view of an electron beam discharge device in accordance with this invention, a portion of the envelope being broken away;

Fig. 2 is an enlarged plan view along the line 2-2 of Fig. 1 showing particularly one illustrative apertured coding plate;

Fig. 3 is a sectional view along the line 3-3 of Fig. 2 showing particularly one illustrative embodiment of a target assembly in accordance with this invention;

Fig. 4 is a perspective view of a section of the target assembly of Fig. 3; and

Fig. 5 is a simplified sectional view of a target assembly, in accordance with this invention, illustrating particularly the electron beam impinging on the collector elements of the target assembly.

Referring now to Fig. 1, there is shown an electron beam discharge device of the flash coder type illustrative of one specific embodiment of this invention. The device, which is further disclosed in the above-mentioned Sears application, comprises an envelope H) having a base H at-- tached thereto and terminals l2 for connection to electron gun means, signal deflection plates, and tilt plates, all not shown, for aligning the wide fiat electron beam with the apertured coding plate, as set forth in the above-mentioned Sears application. These elements may advantageously be positioned by a first set of support rods 13 comprising an internal conducting rod and an insulating cement coating. The support rods It also support a flat hollow shield member or can l4 having trapezoidal sides. A second set of support rods l5 also comprising an internal conducting rod and an insulatin cement coating are in turn secured to the shield can I l and support, in succession, a rectangularly apertured shield plate IS, an apertured coding plate I7, and a target assembly [3 in accordance with this invention. The coding plate El and target assembly [8 are also secured to the envelope H) by a plurality of anchor members l9, best seen in Fig. 3, which are secured to terminals are positioned in the envelope l0.

' Four button terminals, of which only two numbered 22 and 23 are shown in Fig. 1, advantageously are sealed in the end of the envelope l0 and each has secured thereto a lead. These leads include a lead 24 attached to a connection member 25 secured to the coding plate H, a lead 26 .attached to a strut 21 extending from the rectangularly apertured shield plate I6, a lead 28 secured to the inner conducting member of one of the support rods 15 which in turn is connected by a lead 29 to the shield can l4, and a lead 30 secured to the outer shield member 39 of the target assembly l8, as described more fully below. Additionally, a plurality of leads 33 extend from the button terminals 34 positioned around the periphery of envelope I0 adjacent the target asplace.

sembly to terminals attached to the individual output elements of the target assembly l8, as also explained further below.

The apertured coding plate ll, as shown in Fig. 2, may advantageously be of the reflected binary type disclosed in application Serial No. 785,697, filed November 13, 1947 of F. Gray but with certain of the rows of apertures interchanged to further aid in reducing the possibility of the effects of any misalignment. Further th four center codes have been omitted so that they may be used for signaling and other purposes, such as disclosed in C. B. H. Feldman application Serial No. 176,106, filed July 27, 1950. As best seen in Figs. 3 and 5 the apertures are all positioned in a depression 36 in the coding plate I1 and the target assembly i8 is supported by the support rods [5, as by support members 31 secured to the rods l5 by the insulating cement, directly adjacent to the coding plate I! so that each row of apertures in the depression 36 in the coding plate ll is directly aligned with one of the output electrodes of the target assembly I8. I

Referring now to Figs. 3 and 4., one specific illustrative target assembly I8 in accordance with this invention comprises a hollow outer shield member 39 and a plurality of output electrodes 40, il, t2, t3, M, 45, 46 and 4'! shown in this specific illustrative embodiment for an eightdigit code. long narrow strip of a conducting material, as of nickel, mounted on a wider insulating strip 49, as of mica, which extends at its ends through the sides of the outer shield member 39 and is supported thereby. The output strips are secured to the insulating strips 59 by the terminals -51 which are integral with the output strips and are advantageously bent around the strips of insulating material and pinched as by fingers 58,

as best seen in Fig. 4, also integral with the thin.

output electrode strips and extending through apertures in the insulating strips 4-9 and also pinched behind the insulating strips, thereby clamping the output electrode strips securely in Each of the terminals 505'l extend through an aperture 60 in the outer shield member 39 and a lead 33 connects each of the terminals to one of the button terminals 34 in the periphery of the envelope i0.

As can readily be seen in the drawing, the output strips of the target assembly are mounted in a V-shaped array, the base of the V being provided by output strips 49 and 41 nearest the apertured coding plate H and the apex of the V by the output strips 13 and 44 most remote from the coding plate H. As this specific illustrative embodiment comprises an even numbered digit code the apex of the V-shaped array is defined by two output strips whereas in an odd numbered digit code, such as a seven digit code, the apex of the V-shaped array would be defined by but a single output strip or electrode. Each of the output electrodes in each arm of the V is separated from the output electrodes adjacent thereto by an L-section shield member 62 which is supported in and electrically secured to ends of the outer shield member 39. Additionally, a central shield member 63 extends from the apex of the v-shaped array, thus separating the output electrodes 43 and M, to the base of the array between the output electrodes 40 and 41 adjacent the coding plate H. The central shield member 63 is also secured in and electrically attached tothe ends of outer shield member 39 Each collector electrode comprises a central shield member F 63 and extends between the endsof *the'outershield member 39 "behind the apex -of the M shapedarray; 158., behind the output 1 electrodes and 44. 5 Front shield memhers-65 and et-are positioned adjacentto the output electrodes-4i] and respectively-and between them and the apertured coding plate 11 the front shield members 65 andalso-"extend between van'd are supported by" the en'ds of outer shield' member 39. It i therefore apparent that each output electrode in the V-shaped array is substantially surrounded by shieldingmembers and-thus is separated from the neighboring output" electrodes by shielding members.

Fig. 5 a '-simplified =representation of the target assembly showing-the electron beam impinging on the output electrodes,-a signal 'being assumed such that the electron beam has been deriected -to traverse an aperture or slit in each of "the rows in the apertured coding plate and thus impinges on all the output electrodesatthe same time. "Eachof the output electrodes of course extends inalignmentwiththe dig-it columnsof the coding plate so thateach is-individually responsive to the' electron beam current passing through its'associated columnof apertures in the coding plate. By arranging the output electrodes in a V--shaped array, sothat the output electrodes 1 are positioned in staggered planes, a maximum spacing between adjacent electrodes is attained as well as a maximum spacing betweeneachoutput electrode and the shielding members. hs'canbe seen the front shielding members-Gland and'the L-section shielding members GZ are so aligned as' not to interfere with the passage ofthe electron beam from a given column of aperturesin the coding plate to 'a specific output electrode. Thus the L-section electrodes are advantageously of a Widthequal to or less than the spacing'between adjacent columns of apertures in the coding plate l1.

While the shielding members have been disclosed as separate from the outer shield member 39, it is to be understood that they are supported thereby and electrically connected thereto,so that the various shielding members can be considered as a sing1e shield which enables capacitive'and electronic coupling between output electrodes to be maintained at a minimum. Ideally, each of the L-section shield members would extend to the side Walls of the outer shield member 39, but the shorter members, each identical with each other, have been found to provide substantially complete shielding and to simplify greatly the fabrication of the target assembly.

The shield members, which are connected to one of the end button terminals by the lead 30; may advantageously be operated at a negative potential relative to the output electrodesso that any-secondary electrons producedat the-surfaces of the electrodes are suppressed. Alternatively, the output electrodes may be fabricated of a suitable material-to produce a high and uniform secondary emission, in which case the shield members are at a positive potential to collect secondary'electronswhich originate at the output electrodes and thus'provide increased output currents of reversed polarity.

"In'one specific illustrative embodiment of this invention; theshield members were of'nickel and were carbonized to" inhibit secondary emission. T-he outputelectrodes were' strips of nickel .030

inch wide.arid-I1820inches long ar-i'd werel'tormed by a punching operation, the fingers 5B and cut put electrodeterminals being integral with 'the output electrode and 1 for-med at the same time. The insulating members wareot mica inch wide and f 1.882 inches 1 long. The output electrodes were positioned in "thew-shaped array .098 inch from the neighboringoutput electrode in that arm of the array. The overall dimensions of" the outer shield member' '39 of the target assembly were 2.026 inches "long; 0.829inch wide, and inch deep.

It is to be understood that the above-described arrangements are illustrative of the application of *the principles of the invention. Numerous other arrangements "may be -devised r by those skilled "in the art without 'departing -'from the spirit and scope-"of the invention.

What is claimedis:

l. 'A- target assembly for an electron discharge device comprising an outer shield =rnember, "a plurality of targets in said shield member and arranged therein in staggered parallel planes forming a substantially overlapping array, shield means 1 positioned between each i of said targets and the adjacent targets, said shield means together*with said outer shield-member-substantially encompassing each "of 'said targets, and leadmeansassociated with "eachof said targets and extending out of said outer shield 'member.

2. A target assemblyfor' an electrondischarge device comprisin an outer shieldmembena plurality of conducting targets extending in said shield member and arranged therein instaggered planes, shieldmeans positionedbetween each of said targets and the adjacent targets, said shield means including L sectioned' shielding members having one arm extendingxtowards one side of said outer shielding" member and the other arm extendingin the direction'ofelectron flowin said device, said shield means together with said shield member substantially encompassing each of said targets while allowing ingress of electrons to impinge on each of said targetsyand leadmeans associatedwith'each of said targets and extending out of "said outer shield member.

*3. A target assembly for anelectronidischarge device comprising an outer shield :m'embena plurality of conducting targets extendingin said shield member and arrangedtherein instaggered planes, insulating means independently support: ing each of saidtargets'from the ends of said membenshield means "positioned between each of said-targets and the adjacent targets, said shield means including L-sectioned shielding membershaving one arm extending towards one side of said outer shieldmember and the other arm extending inthe direction ofelectron flow insaid device, said shield means together with said shield member substantiallyencompassing each'of said targets while allowing ingress of electrons to impinge on each of said targets, and lead-means associated with. each of said targets and extending'out' of said outer shield. member, saidlead means comprising terminals integral with saidconductingtargets and bent over behind said insulating means to clamp said conducting targets to' said insulating means.

4. A target assembly for an electron discharge device comprising an outer shield member, aplurality of targets extending in said shield member and arranged therein in a substantially V-shaped array, shield means; positioned between adjacent targets" in said array, said' shield means together with said shield member substantially encompassing each of said targets while allowing ingress of portions of an electron beam to each of said targets, said shield means being of width substantially equal to the spacing between the portions of the electron beam directed toward each of said targets, and lead means associated with each of said targets and extending out of said outer shield member.

5. A target assembly for an electron discharge device comprising an outer hollow shield member having side and end portions, a plurality of conducting strips extending the length of said member and arranged therein substantially in a V-shaped array, insulating means independently supporting each strip from the ends of said member, shield means between each of said strips in said array, said shield means together with said hollow shield member substantially encompassing each of said strips, and lead means associated with each of said strips and extending out of said outer shield member.

6. A target assembly for an electron discharge device in accordance with claim wherein said lead means comprises terminals integral with said conducting strips and bent over behind said insulating means to clamp said conducting strips to said insulating means.

7. A target assembly for an electron discharge device in accordance with claim 6 wherein said insulating means have apertures therethrough and comprising fingers integral with said conducting strips extending through said apertures and bent over behind said insulating means to clamp said conducting strips to said insulating means.

8. A target assembly for an electron discharge device comprising a hollow shield member having side and end portions, a plurality of narrow conducting strips extending the length of said member and arranged therein substantially in a V- shaped array, an insulating member supporting each of said strips from the ends of said member, shield means between each of said strips in said array, said shield means comprising substantially L-section members having one arm extending towards the base of said V-shaped array and the other arm extending towards one side of said hollow shield member, and lead means associated with each of said strips and extending out of said hollow shield member.

9. A target assembly for an electron discharge device comprising a hollow outer shield member having side and end portions, a plurality of narrow conducting strips extending in said hollow member and arranged therein substantially in a V-shaped array, an insulating strip supporting each of said conducting strips from the ends of said shield member, lead means associated with each of said conducting strips and extending out of said hollow shield member, said lead means comprising terminals integral with said conducting strips and bent over behind said insulating strips to clamp said conducting strips to said insulating strips, and shield means between each of said conducting strips in said array, said shield means comprising a plurality of substantially L-section members which together with said hollow outer shield member substantially encompass each of said strips.

10. A target assembly for an electron discharge device in accordance with claim 9 wherein said insulating strips have apertures therethrough and comprising fingers integral with said conducting strips extending through said apertures and bent behind said insulating strips to clamp said conducting strips to said insulating strips.

11. A targetassembly for an electron discharge device comprising an outer shield member having side and end portions, a plurality of narrow conducting strips extending the length of said member and arranged therein substantially in a V- shaped array, said plurality being an even number and the apex of said array comprising two of said strips, an insulating strip supporting each of said conducting strips from the ends of said shield member, and shield means between each of said conducting strips, said shield means comprising a central shield plate secured to the ends of said hollow shield member and extending from between said two conducting strips at the apex of said array to the base of said array, a back shield plate secured to said central plate and to the ends of said array, a plurality of L-section shield members secured to the ends of said outer shield mem--, ber and positioned between adjacent conducting strips in each arm of said array, one arm of said L extending towards the base of said array and the other arm of said L extending towards one side of said shielding member, and front shield members positioned adjacent the conducting strips in the base of said array and secured to the ends of said outer shield member, said shield means and said outer shield member substantially encompassing each of said conducting strips while allowing ingress of an electron beam to impinge on said conducting strips, and lead means associated with each of said strips and extending out of said hollow shield member.

12. A target assembly for an electron discharge device in accordance with claim 11 wherein said lead means comprises terminals integral with said conducting strips and bent over behind said insulating strips to clamp said conducting strip to said insulating strips.

13. An electron discharge device comprising an apertured coding plate having a plurality of rows of apertures therein, means removed from said plate and to one side thereof for projecting and focussing an electron beam against said plate, and a target assembly adjacent said plate to the other side thereof, said assembly comprising a hollow shield member having end and side portions, a plurality of conducting strips extending in said shield member and arranged therein in a substantially V-shaped array, one of said strips being aligned directly behind each of said rows of apertures in said coding plate, insulating members extending between the ends of said shield member, one of said insulating members supporting each of said conducting strips, and shield means between adjacent conducting strips in said array, said shield means and said outer shield member substantially encompassing each of said conducting strips but defining discrete paths for the electrons emerging through said apertured coding plate to impinge on said conducting strips.

14. An electron discharge device comprising an envelope, an apertured coding plate having a plurality of rows of apertures therein positioned within said envelope, means removed from said plate and to one side thereof within said envelope for projecting and focussing an electron beam against said plate, a target assembly adjacent said plate to the other side thereof, a plurality of terminals extending through said envelope adjacent said target assembly, said target assembly comprising a hollow shield member having end and side portions, a plurality of nar-f row conducting strips extending the length of said member and arranged therein in a substantially V-shaped array, one of said strips being aligned directly behind each of said rows of apertures in said coding plate, insulating strips extending between the ends of said shield member and supported thereby, shield means between adjacent conducting strips in said array, said shield means and said outer shield member substantially encompassing each of said conducting strips but defining discrete paths for said electrons emerging through said coding plate to impinge on said conducting strips, and terminals integral with said conducting strips and bent over behind said insulating strips to clamp said conducting strips to said insulating strips, and lead means connecting each of said conducting strip terminals to one of said terminals extending through said envelope.

15. An electron discharge device in accordance with claim 14 wherein said insulating strips have apertures therein and comprising fingers integral with said conducting strips extending through said apertures and bent over behind said insulating means to clamp said conducting strips to said insulating means.

16. An electron discharge device in accordance with claim 14 wherein said shield means includes L-section shielding members secured to the ends of said outer shield member and positioned between adjacent conducting strips in each arm of said array.

17. An electron discharge device in accordance with claim 16 wherein one arm of the L of said L-section shielding members extends towards said apertured coding plate and the other arm of said L extends towards one side of said shielding member, said arm extending towards said apertured coding plate being of a width at least no greater than the distance between adjacent rows of apertures in said plate.

18. An electron discharge device comprising an envelope, an apertured coding plate having a plurality of rows of apertures therein positioned within said envelope, means removed from said plate and to one side thereof within said envelope for projecting and focussing a flat wide electron beam on said plate, a target assembly adjacent said plate to the other side thereof, a plurality of termina1s extending through said envelope adjacent said target assembly, said target 10 assembly comprising a hollow outer shield member having end and side portions, a plurality of narrow conducting strips extending the length of said member and arranged therein in a substantially V-shaped array, said plurality being an even number and the apex of said array comprising two of said strips, one of said strips being aligned directly behind each of said rows of apertures in said coding plate, insulating strips supporting each of said conducting strips from the ends of said shield member, shield means between each of said conducting strips, said shield means comprising a central shield plate secured to the ends of said hollow shield member and extending from between said two conducting strips at the apex of said array to the base of said array, a back shield plate secured to said central plate and to the ends of said array, a plurality of L-section shield members secured to the ends of said outer shield member and positioned between adjacent conducting strips in each arm of said array, one arm of said L extending towards said apertured coding plate and the other arm of said L extending towards one side of said outer shield mmeber, and front shield members positioned adjacent said conducting strips at the base of said array between said base conducting strips and said coding plate, said shield means and said outer shield member encompassing each of said conducting strips but defining discrete paths for said electrons emerging through said apertured coding plate to impinge on said conducting strips, and terminals integral with said conducting strips and bent over behind said insulating strips to clamp said conducting strips to said insulating strips, and lead means connecting each of said conducting strip terminals to one of said terminals extending through said envelope.

HERBERT C. JONAS.

RAYMOND W. SEARS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,190,069 Hollmann Feb. 13, 1940 2,202,376 Hansell May 28, 1940 2,361,766 Hadekel Oct. 31, 1944 2,458,652 Sears Jan. 11, 1949 2,472,779 Selgin June 7, 1949 2,532,747 Van Gelder et a1. Dec. 5, 1950 

